This invention relates to an apparatus and method for the manipulation of materials, including macromolecule s, such as proteins, nucleic acids and other moieties, in fluid samples.
Since Nobelist Richard Feynman first urged scientists and engineers in 1959 to pursue ultra-small technology, numerous devices have been described in the art for the miniaturization and minimalization of analytical systems.
Austin et al. in U.S. Pat. No. 5,427,663 describe a microlithographic array for macromolecule and cell fractionation. This apparatus has channels of a depth commensurate in size to that of the microstructures in the fluid sample, so that the microstructures are restricted to flow in essentially a single layer. The use of traditional etching techniques limits the depth of the channels.
Heller et al in PCT Publication No. WO 95/12808 describe a self addressable self-assembling microelectronic system and device which can actively carry out controlled multi-step and multiplex reactions in microscopic formats. The device has a matrix of addressable microscopic locations on its surface.
Pace, in U.S. Pat. No. 4,908,112, teaches the use of micro-fabrication techniques to produce a capillary gel electrophoresis system on a silicon substrate. Multiple electrodes are incorporated into the system to move molecules through the separation medium within the device.
Branebjerg et al., in xe2x80x9cFast mixing by Laminationxe2x80x9d, Proceedings of the Conference on MEMS, Feb. 11-15, 1996, San Diego, Calif., disclose a micromachined device for mixing of small flowing fluid volumes.
Klaassen et. al. in Sensors and Actuators A 52:132-139(1996) disclose developments in the technique of deep reactive ion etching (DRIE), which when combined with silicon fusion bonding (SFB), make it possible to etch nearly the entire range of microstructure thicknesses in single crystal silicon.
The disclosures of the foregoing patents and publications are incorporated herein by reference.
Despite these advances in the art, there remains a need to efficiently extract analyte from large volumes of raw specimen and then to elute the analyte into a very small volume to assure that the final concentration is above the detection limit of the assay method. Prior art devices are generally not compatible with microfluidics nor easily integrated into small analytical systems. None of the prior art methods is efficient nor able to concentrate extracted materials. The present invention overcomes many limitations of the prior art devices for extraction and purification of materials from fluid samples, including biological specimens.
This invention comprises an apparatus and method for the manipulation of materials, including macromolecules, such as proteins, nucleic acids and other moieties, in fluid samples. The apparatus comprises an enclosed chamber on a chip having an internal microstructure with surface area substantially greater than the facial surface area of the internal structure. The chip may contain integrated heating elements. The internal structure may present an inert, non-reactive surface, or be coated with a reactive ligand, or be electrically conductive and optionally be coated with an electrical insulator. Discrete portions of the internal structure may differ in microstructure and surface properties from other portions.
Generally the internal microstructure comprises a continuous network of channels, each of which has a depth substantially greater than its width. The network may comprise a single channel, a single channel with multiple branches, multiple channels, multiple channels with multiple branches, and any combination thereof.
In one embodiment, the network of channels is so extensive so as to form an internal structure which comprises an array of non-contiguous microcolumns. This embodiment may alternatively be considered as an enclosed, high surface area chamber, having a plurality of independent, non-contiguous columns within said chamber, and at least one port, wherein said columns selectively interact with materials in the sample. In this embodiment, the columns may extend across the smallest dimension of the chamber and may optionally be provided with a coating which selectively retains target moieties, including macromolecules, particularly nucleic acids. Likewise, the columns may be electrically conductive and optionally covered with an electrical insulator.
Also provided is a general method for manipulating charged materials in a fluid sample by contacting the sample with a thin film electronic extractor having an insulator film and an underlying conductor to which a voltage is applied.